Castroides. Skull of the giant Pleistocene beaver (top) compared with the skull of the living form. The history of the beaver is typical of the history of many mammals in that the living forms are smaller than their leistocene predecessors. In general, the larger members of any fauna disappear in times of stress. Stokes, 1960, p. 444.

Disjunct distribution, evolution and mixing. Subspecies 'taeniata' is a salamander in Western Europe; 'salamandia' in Eastern Europe. Mixed in Germany where they can interbreed. Before glacial advances habitat was continuous, became divided by advancing ice into West and east area where evolution led to two distinct subspecies. When ice retreated, both subspecies followed north and met in mixed area where they can still interbreed.

Archaeology. Earliest drawings from the New World, showing mastodon, tapir and bison (McGowan and Hester, 1962, p. 172).

Extinction dates of the Pleistocene mammals in North America. More than half of these 16 mammals seem to have died out between 10,000 and 8,000 years ago. (McGowan and Hester, 1962, p. 196).

Megatherium, Pleistocene ground sloths. These are edentates characterised by unusually long large bodies anf lengths up to 20 feet. They occur in both North America and South America, the latest being contemporaries of early man. The name Megatherium means huge beast. Moore, 1958, p.551.

Woolly mammoth, Mammuthus primigenius. Best known and most characteristic animal of the Ice Age. The elephant, about 12 feet in average height was characterised by its relatively large head and unusually long curved tusks. Its body was covered by long, dense hair. Specimens found in frozen ground of Siberia and abundant remains occur in North America. Moore, 1958, p. 550.